In general, medical practices of injecting a chemical liquid or nutrition into a blood vessel, collecting and testing blood, and dialyzing blood by circulating the blood out of the body are widely carried out through a catheter inserted into/indwelling in the blood vessel.
While a thrombus-aspiration catheter for aspirating a thrombus formed in a cardiac coronary artery is known thereamong, this is a catheter directly aspirating the thrombus growing in the coronary artery in order to prevent such an acute myocardial infarction that the thrombus formed in the coronary blood vessel stops the bloodstream and reduces the cardiac functions.
This thrombus-aspiration cure is a therapy of aspirating and eliminating the thrombus itself by inserting a thin tube of about 1.3 to 2.0 mm in diameter referred to as a thrombus-aspiration catheter from a leg or an arm and making the same reach the lesioned portion in the coronary artery. In the thrombus-aspiration cure, the thrombus, which is the cause constricting the blood vessel, itself is eliminated, whereby risks such as occlusion of the coronary artery with a thrombus not completely dissolvable with a medicine and scattering of the thrombus to coronary artery periphery resulting from dilation with a balloon catheter having been present in a conventional cure can be avoided.
The thrombus-aspiration catheter requires a certain degree of strength so that the wall surface of the catheter is not crushed by negative pressure, and an area (opening area) in an opening section is preferably maximized in order to easily discharge the thrombus from the body.
Thrombus-aspiration catheters include that prepared by inserting a core wire into a tube in order to transmit force for thrusting the catheter necessary for easily inserting the same into a curved blood vessel and to prevent kinks and that prepared by embedding a reinforcing body formed by a metal mesh into a tube. A guide wire is previously inserted into the blood vessel and the thrombus-aspiration catheter is inserted along this guide wire, and hence the front end portion of the thrombus-aspiration catheter is constituted of an aspiration lumen for aspiration and a guide wire lumen for inserting the guide wire.
The front end portion of the catheter is preferably flexible, to be easily inserted into the curved blood vessel.
As a precedent, a thrombus-aspiration catheter improved in aspiration property and cross property by forming a front end opening as an inclined cut surface has already been applied by the applicant (refer to Patent Document 1, for example).    Patent Document 1: Japanese Patent Laying-Open No. 2004-222946